In ordinary construction, exterior walls are primarily made of which type of material?

In ordinary construction, exterior walls are primarily made of noncombustible or limited-combustible materials. This characteristic is crucial for fire safety, as it helps to prevent the spread of fire and offers some degree of fire resistance. Noncombustible materials, such as masonry, concrete, and steel, do not ignite or contribute fuel to a fire, which is vital in residential and commercial buildings to protect occupants and reduce damage.

Limited-combustible materials, on the other hand, may burn but at a significantly slower rate and only under certain conditions. This balance makes them suitable for use in exterior walls, where fire control and safety are paramount. In contrast, materials classified as fire-resistive are designed to withstand fire for specific periods but are often used in specific applications such as fire-rated walls and barriers, rather than typical exterior construction.

Highly combustible materials are not typically used for exterior walls in ordinary construction due to their propensity to ignite quickly and contribute to fire spread. Likewise, heavy timber, while sometimes permitted in certain codes, is not the primary choice for exterior walls in ordinary construction because of its potential for combustion and is generally used in more specialized construction types.

Thus, noncombustible or limited-combustible materials